The present invention relates to a graphic processing apparatus for generating, displaying or printing characters and graphic data, and more particularly to a graphic processing apparatus including a frame buffer provided integrally in a main memory to store display pixel data and a graphic processing method of generating characters and graphic data.
A graphic processing apparatus for generating and displaying characters and graphic data includes a frame buffer for storing data corresponding to pixels on a display screen. In order to display a stable picture on the display screen, it is necessary to read data from the frame buffer successively repeatedly in synchronism with the raster scanning of a display unit. In order to realize the display function, the frame buffer is generally used as a memory independently of a main memory.
Japanese Patent Unexamined Publication JP-A-59-131979 discloses, as a special purpose memory suitable for the frame buffer, a graphic dual-port memory having a serial output port in addition to a random access port. The use of the memory can make short the display access and hence improve the drawing performance (graphic generation). However, thereafter, even if the integration density of the memory is increased, a constant number of memories are required to obtain a fixed display output. Accordingly, there is a problem that the high integration is not utilized in a lower capacity area of the memory effectively.
Further, there are Japanese Patent Unexamined Publications JP-A-63-91787 and JP-A-1-265348 as relevant references.
Heretofore, there is a problem that the access method which is complicated and low in a speed must be utilized in order to cope with various applications. Further, there is a problem that the high integration of the graphic dual-port memory capable of being used as the high-speed frame buffer is not utilized for a small capacity memory.